Method of forming metal blanks of varying cross-section



A. L. PUTNAM- METHOD OF FORMlNG METAL BLANKS 0F VABYING CROSS SECTION.

APPLICATION FILED MAR, 7, X918,

Patented ManZZ, 1921 1,372,;QAG.

(Maw-Vega .ltLlDEN 1'4. P'UTNAM, F

DETROIT, MICHIGAN, ASSIGNQR, BY MESNE .MSlSIGNMiElTTS, "330 I MUN OF DELAWARE.

METHOD or romaine ri s'ra thtttmwis or van'rrne cnoss sncrroni Application filed.March 7, 1918. Serial No. 220,918.

To all ham it may concern:

Be it known that l, ALDEN L. PUTNAM, a citizen oi the United States of America, residing at Detroit, in the county of l fayne and ldtate of Michi 'an have invented certain new and useful Improvements in Metheds oi? l1 orming Metal Blanks of Varying; tlross-fdection, of which the following is a specification, reference being bad therein to the accompanying drawings.

T he invention relates to the manufacture oi sheet-metal blanks oi? varying cross-section, being more particularly designed for i use in the manufacture of disk wheels but ill] ' applicable also to other articles. It is the object of the invention to simplify the operation of machining or otherwise removing the metal and also to produce uniformity in results.

ln the manufacture of disk wheels the center portion of the blank, or that portion. which is secured to the hub, is oi greater c. than the' peripheral port 11 which bed to the rim or rally. rue forging such a blank, particularly where the disk is c relatively li' bt gage metal, is a diihcult operation, and consequently blanks are frequently formed by machining irom stock oi? the nutximum lit is however, necessary to accurately taper the section, which requires skillful WOTlUIlttIlSlllP when pertermed upon ordinary machine tools. W 1th my improvement thc blank to be machii'ied first conformed to a master so fashioned that a plane cut acro s the opposite side of the blank will produce the desired variation in gage in all portions thereof. For iheavy work the flat blank may be first pressed into approximate'r'orm to fit the master, it for the lighter gage work the blank may be conformed merely by clamping pressure.

ln the drawings 1 have; illustrated my method as applied to the forming of a taperingdisk for a vehicle wheel, and Figure 1 is a cross section through the master showing the fiat blank to be conformed thereto; Fig. 2 is a similar viewafter the clamping pressure has been applied; Fig. 3 is a similar view after the out has been taken to remove the surplus metal; Fig. 4 is a section through the blank removed from the master; and

Fig. 5 is a section of the blank pressed to its final form.

A is the master which .is a rigid block splicificatidn of Letters Patent.

Patented liter. $252, limit;

upper face of preferably of cast-metal, the

which has been fashioned to the desired form. As shown the central. portiouis dcpressed, as shown at lhand between this cen-- tral portioiii and tlreperiphery; is a tapering; H conical portion D is accntral threaded 6 aperture :tor engaging; .a .clamping bolt ll'L. and l is a clamping plate engaging; the bolt l i it. circular blank of which is equal. to the maximum gage of the finished blank, is tl'ien placed upon the master, as-indicatcd at H. The bolt E is then passed throughthe central aperture; in the blank'and into engagement with the threaded aperture D and clamping pressure aplied, which will draw the centralaportion of the blank downward and will at the same time cause all portions oi the blank intermediate the center and the periphery to accurately conform to the shape of the master. When clamped, as shown in Fig. 2, a plane cut is taken across th e major p on oi: the

metal, the gage ot lQll after being deflected to exposed surface or the blanlr, thus as shown in. Fig. 3, this cut heen tar on the on tion adjacent the p ii ihery which it is not desired to sat portion home cut par allel to the conical sur f the blank is removed, as shown in hi, all,

oi fall a port1on ac ge and an errncdiate L 4 tion which will be tapering. the account oi:

to which. it is subjected in clamping all per tions of the lower into close proximity; to the abutting lace out the master and w ll during the machltmng operation. This ;.would notbe the case it the ilat blank were 9 because the blank is seldom perfectly true; and second, because there is danger that spring away from the bed under the ma chi-mug operation. llhus my improved and uniform results as well as simplifying; the operation.

a degree not exceechng its elastic limit, released from the master the resiliency of tire exposed surface excepting only por-- so "face 0. lhus it will/have its central portion l of ably reduce the resiliency out the metal and the pressure ice-will be brought be held in firm contact merely bolted to a flat table or bed,---[irst,

portions not close to the clamping screw may method has the advantage of more accurate When the blank,

the metal will cause it to spring back to its original plane, unless it has been conformed to the master by a preliminary die operation. If it is desired to impart to the structure a permanent dished shape this may be performed by a subsequent pressing operation, as indicated in Fig. 5.

In case the above described process is being applied to fashioning blanks from comparatlvely-heavy gage metal, the same apparatus and same steps will be employed, the only difler'enc'e being that there will be a preliminary step of slightly dishing the disk by the use of suitable dies so as to conformv the blank either wholly or in part to the master. Ll he tightening of the bolt ll will obviously serve primarily to clamp the (lie-formed blank to the master, deflecting the same very little, if any. For light gage metal thepreliminary die operation is unnecessary.

What I .claim as my invention is:

1. The method-of forming sheet-metal blanks of varying cross-section, comprising conforming one face of a blank of uniform gage to the fashioned face of a master and taking a plane cut across the exposed face of said blank.

'2. The method of forming sheet-metal blanks of varying cross-section, comprising the clamping of the blank to a. master having a fashioned face to conform one face of the blank thercto and taking a plane cut across the exposed face of the blank.

3. The method of forming shcet -inctal blanks of varying; cros section, comprisin the clamping: of a uniform gage blank to a master liming a. fashioned face so to spring the metal into conformity to said face, and taking a. plane cut across the opposite face.

at. The method, of .t'ormin circular \rliccl blanks of tapering: cross scction, comprising the clan'iping of a blank of uniform crow section to a master having av fashioned l'acc with a central depression and a portion llaring or tapering thcrcl'rom toward the pcriphery, and taking; a plane cut across the opposite face of the blank.

5. The method of forming sheet metal blanks con.'=.istin; in clamping a sheet metal blank to a non-parallel surface so as to place the metal under ELHSiOIL and in machining the blank while so tcwsioncd.

In testimony whereof I aiiix my signature. 

